This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Influenza, avian influenza, varicella, and SARS belong not only to the most virulent viruses known to human kind but are also spread by the airborne route. Strategies to prevent and control the often explosive outbreaks associated with these pathogens are limited to vaccination and treatment, if available, or isolation and barrier precautions. The latter includes the utilization of face masks to interrupt the chain of transmission. However, the scientific evidence regarding the efficacy of face masks has been solely based on studies using mannequin heads and non-viable tracers and/or bacteria. We propose to develop a model for the airborne dispersal of viable viral pathogens (human rhinovirus) and for testing the efficacy of barrier precautions such as face masks in human subjects. In the first aim, we will establish a test procedure to disperse particles in defined sizes (1 and 10 [unreadable]m) containing preset amounts of rhinovirus.